Just days after winning Round 1 of its patent-infringement case against Microsoft, VirnetX has filed another patent-infringement case against the Redmondians. This time, VirnetX is taking aim at Windows 7.

Kevin Kutz, Director of Public Affairs, said Microsoft hadn't yet seen VirnetX's new claim.

"While we can't comment specifically about the new complaint because we have not been served, Microsoft respects intellectual property, and we believe our products do not infringe the patents involved. Moreover, we believe those patents are invalid. We will challenge VirnetX's claims."

A Texas jury on March 16 recommended Microsoft pay VirnetX $105.75 million for willfully infringing on two VirnetX networking patents. Microsoft officials said they are appealing that ruling.

McKool Smith, the law firm representing VirnetX is the same one that represented i4i, which won a $200-million-plus patent-infringement verdict against Microsoft. Judge Leonard Davis, the same judge who presided over the i4i case, was the judge overseeing the VirnetX case, as well.

VirnetX, a subsidiary of VirnetX Holdings, is “focused on commercializing a patent portfolio for securing real-time communications over the Internet,” explains the company in its November 10-Q.

Update: I just received more on VirnetX's new suit, which it filed on March 17, 2010. Here's VirnetX's official statment:

VirnetX "filed a complaint in the Tyler Division of the Eastern District of Texas alleging infringement of U.S. Patent Nos. 6,502,135 and 7,188,180 by Microsoft's Windows 7 and Windows Server 2008 R2 software products."

“This is a tactical and procedural post-trial action to ensure and protect our property rights as we proceed to final resolution with Microsoft,” said Kendall Larsen, VirnetX President and CEO.